Polish Prime Minister Donald Tusk said on Tuesday that Poland prevented what appeared to be an attempted provocation on its border with the Russian exclave of Kaliningrad overnight.

Tusk gave few details but said that “individuals with flashlights” had been observed in the border area and that Polish guards prevented any incident from happening. According to the prime minister, additional police and other troops, including counterterrorism units, were directed to Poland’s northeastern border regions after authorities received “more precise” information that acts of sabotage, including a potential incursion by “armed people”, were possible in the first half of November. Members of Poland’s GROM special operations unit were deployed to the border with Kaliningrad to take part in a police operation aimed at preventing “planned acts of sabotage”, according to Russian state agency TASS; Tusk announced the deployment ahead of a cabinet meeting. Tusk said it was not possible to confirm with full certainty that the incident was an attempted provocation, and that Russia’s escalation would continue and was unlikely to be limited to that episode.